The overall objective of the proposed work is to define the role of the renal nerves in directly influencing renal tubular sodium transport in the normal animal. Utilizing anesthetized dogs, studies involving both direct and reflex stimulation of the renal nerves will be performed to delineate a role for the neural control of tubular sodium reabsorption. Known antagonists of neuroadrenergic transmission will be employed to identify and verify direct adrenergic innervation of renal tubular segments. BIBLIOGRAPHIC REFERENCES: Kaloyanides, G.J., DiBona, G.F. and Bastron, R.D.: Effect of Blood Volume Expansion on Tubule Sodium Transport in the Isolated Dog Kidney. Prog. Soc. Exp. Biol. Med. 148;765-773, 1975. Norby, L.H. and DiBona, G.F.: The Renal Vascular Effects of Meglumine Diatrizoate. J. Pharmacol. Exp. Ther. 193:932-940, 1975.